This allows MENU resources to be serialized.
MENU resource statement doc: msdn.microsoft.com/en-us/library/windows/desktop/aa381025.aspx
POPUP sub-statement doc: msdn.microsoft.com/en-us/library/windows/desktop/aa381030.aspx
MENUITEM sub-statement doc: msdn.microsoft.com/en-us/library/windows/desktop/aa381024.aspx
MENUHEADER structure: msdn.microsoft.com/en-us/library/windows/desktop/ms648018.aspx (and NORMALMENUITEM, POPUPMENUITEM structs).
Thanks for Nico Weber for his original work in this area.